The present invention relates to the field of automated job management, and in particular the monitoring and control of equipment processing in a semiconductor fabrication facility.
Semiconductor chip manufacturing does not typically enjoy the high level of automation that other technology sectors do. In various areas of a semiconductor chip manufacturing factory, the systems and tools are often only semi-integrated or even completely independent. Furthermore, because of the proprietary communication protocols that are typically used, it is often very difficult to automate the manufacturing process in a way that not only coordinates the activity between the tools, but also collects data from the tools in a fashion that is usable for process improvements and other job management functions.
In a typical configuration, tools are grouped together and loosely controlled by a monolithic software program known as a “station controller.” A typical station controller communicates with either an individual tool or a group of tools using an industry standardized interface known as SECS/GEM. SECS/GEM is present on most tools using 300 mm silicon wafers to produce semiconductor chips, and is also the standard communication interface in factories where 200 mm wafers are used. The needs of 300 mm and 200 mm factory types are very different, but both typically use a station controller in certain parts of their operations.
Current software architectures implementing station controllers have severe restrictions, in particular with respect to integration among semiconductor manufacturing tools and the way that data about tool actions and status is handled. Where there is a need for the equipment to provide real-time data directly from the tools to other software applications for the purpose of manufacturing process analysis, diagnosis, and quickly implemented corrective actions, the current software architectures used to integrate and extract data from the tools has many design impediments to overcome.
One limitation is that the legacy solutions in place currently collect data from semiconductor equipment that is managed by station controllers using a single client SECS/GEM communication protocol. Thus, only a single client can communicate with each tool and the available data set is driven by data availability in the SECS/GEM interface specification. The SECS/GEM interface does not reveal the structure of the equipment, making it impossible to determine the physical makeup of equipment. In addition, SECS/GEM is not a discoverable interface, so applications cannot query the equipment to determine its capabilities. Also, SECS/GEM has no security mechanism, so there is no concept of client authorization and access permissions in SECS/GEM. Finally, the single client limitation means that there is no support for simultaneous multi-client access to equipment information.
Another fundamental problem present in current station controllers is higher complexity as a result from a drift from the primary function of controlling material processing. As multiple functions have been incorporated on top of core job management needs, large and complex software architectures have been created that are not easily adaptable to change. This also results in a single point of failure with multiple internal failure points and a high cost of ownership. Because data collection has typically be integrated with job management, current station controllers have become the sole collectors of equipment data, requiring data consumers to interface through the station controllers.
The changes in the semiconductor industry that have mandated that semiconductor manufactures implement efficient automation integration strategies is primarily attributed to the resulting exponential increase in manufacturing data that must be managed as circuit capacity increase with 300 mm wafers and beyond, in parallel with reductions in geometry size which are now focused on 45 nm and below. In addition to the above drivers for change, several other pressures are magnifying the need for change. First, a need exists to focus a small number of expert resources on solving issues, and to reduce the resources spent on merely finding data. Also, the high cost of mis-processing wafers at 45 nm, where each wafer consists of 100's to 1000's of die, has made the need for efficient solutions more acute. There are also performance issues that are driving the need for efficient solutions, such as the high cost of equipment downtime and the desire to improve overall equipment effectiveness (OEE). There is also a need for real-time data to allow faster response to processing issues and a need to improve the tool to production time.
Current solutions will not solve the data access requirements for applications such as e-Diagnostics and Advanced Process Control (APC) that require the ability for automation architectures to support concurrent multi-client access to equipment and independent of the current ownership of equipment processing control. The ability to implement “data on demand” is a driving factor in the next generation of semiconductor focused station controller architectures. As the industry moves from lot based to wafer level manufacturing, automation solutions will need to be able to provide advanced statistical process control (SPC), fault detection classification and run-to-run control applications required to make effective manufacturing and business decisions to meet the demands of their customers.
For the reasons stated above, the typical station controller has become an impediment. Where once the station controller was designed to specifically control management of manufacturing jobs, now the station controller has evolved into an intricately intertwined set of programs whose functions have expanded as much as its complexity. This complexity makes maintenance or changes to the station controller, as well as to its fundamental functions such as job management, very difficult, time consuming and expensive. In some cases the overlapping and intertwined nature of the software code makes factory managers very hesitant to make any changes, even if they would result in manufacturing process improvements that are required in order to increase the output yields of operating semiconductor chips.